The Design And Implementation Of High-performance The Jave SAX Parser

XML (extensible Markup Language) is designed to define various kinds of XML documents, which are widely used in the data transmission, data transition, data integration and document storage under Web environments. The XML parsing interface SAX (Simple API for XML) first appears in an open forum named XML-DEV. It is based on event-driven model which triggers a series of events for user's handling while parsing a XML document. Although SAX doesn't become an official recommended standard, it is actually widely adopted among developers and end-users.This thesis covers the design and implementation of a high performance SAX parser Once SAXParser. Once SAXParser has complete XML-parsing function, as well as scaliable and extensible architecture. We also made great efforts in the design to enhance Once SAXParser's performance, such as simple data structure, effective finite automaton implementation, buffer management in lexical analyzer and state simplization of syntax parser. What's more, we tried object-pool technology to reduce the CPU usage in objects' creations and destructions, as well as some useful performance improvements in the programming language level.In order to test the function and interface comformance of Once SAXParser, we also built the XML comformance test suite for it. This suite extends the JUnit automation test architecture, which can automatically test more than 2,000 comformance testing cases. The final results show that Once SAXParser successfully passed all the cases in which most other parsers failed to pass.In the last, we tested Once SAXParser's performance as well as the most popular Xerces with the XML Test suite tool from SUN microsystem. The results turned out to be a 30% performance advantage of our parser over the Xerces SAX Parser. So we come to the conclusion that the design and implementation of Once SAXParser is effective, together with function integrity.